simplicity sunstar with magnum 18 oil leak

I have a Simplicity Sunstar with a Kohler 18hp magnum engine. When I first got this it had been sitting and the fuel was not getting through. I cleaned entire fuel system including carb and replaced float and needle valve. Still didn't run correctly. It had spark but was weak I replaced the module and now starts right off. It had a little oil leak at valve covers so replaced them with module with help from my brother-in-law. It sat at his place for over a year before he got it dug out and delivered it back. Just started it yesterday and oil seems to be poring out under the Carb. It looks like it is coming out on thread side of the block bolt.This motor smokes some but sounds and runs great after earlier mentioned repairs. Any ideas? I did pull that screw out and put gasket sealer in the threads but have not started it to give it a chance to setup.